package org.young.admin.common.config.shiro;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.apache.shiro.web.util.WebUtils;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;
import org.young.common.bean.Result;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

/**
 * @author young
 */
@Slf4j
public class JwtFilter extends BasicHttpAuthenticationFilter {

	private static final String X_ACCESS_TOKEN = "X-Access-Token";

	public JwtFilter() {
	}

	/**
	 * 执行登录认证
	 *
	 * @param request
	 * @param response
	 * @param mappedValue
	 * @return
	 */
	@Override
	protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
		try {
			executeLogin(request, response);
			return true;
		} catch (Exception e) {
			this.sendChallenge(response, e);
		}
		return false;
	}

	/**
	 *
	 */
	@Override
	protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
		HttpServletRequest httpServletRequest = (HttpServletRequest) request;
		String token = httpServletRequest.getHeader(X_ACCESS_TOKEN);
		if (token == null) {
			token = httpServletRequest.getParameter("token");
		}
		JwtToken jwtToken = new JwtToken(token);
		// 提交给realm进行登入，如果错误他会抛出异常并被捕获
		getSubject(request, response).login(jwtToken);
		// 如果没有抛出异常则代表登入成功，返回true
		return true;
	}

	/**
	 * 对跨域提供支持
	 */
	@Override
	protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
		HttpServletRequest httpServletRequest = (HttpServletRequest) request;
		HttpServletResponse httpServletResponse = (HttpServletResponse) response;
		httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
		httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
		httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
		httpServletResponse.setHeader("Access-Control-Allow-Credentials", "true");
		// 跨域时会首先发送一个 option请求，这里我们给 option请求直接返回正常状态
		if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
			httpServletResponse.setStatus(HttpStatus.OK.value());
			return false;
		}
		return super.preHandle(request, response);
	}

	protected boolean sendChallenge(ServletResponse response, Exception e) {
		log.debug("Authentication required: sending 401 Authentication challenge response.");
		HttpServletResponse httpResponse = WebUtils.toHttp(response);
		httpResponse.setStatus(HttpStatus.UNAUTHORIZED.value());
		httpResponse.setCharacterEncoding("utf-8");
		httpResponse.setContentType("application/json; charset=utf-8");
		try (PrintWriter out = httpResponse.getWriter()) {
			Result fail = Result.error(String.valueOf(HttpStatus.UNAUTHORIZED.value()), e.getMessage());
			out.print(JSONObject.toJSONString(fail));
		} catch (IOException ioException) {
			log.error("sendChallenge error：", e);
		}
		return false;
	}
}
